During ophthalmological surgeries, various volumetric and vacuum pumps have been used to remove fluid and other material from the surgical site. For example, in ophthalmic surgical systems, a peristaltic pump may be used to regulate the flow of fluid from and to the surgical site during vitrectomies, cataract removals, and other ophthalmic procedures. Such peristaltic pumps have the disadvantages of introducing a pulsatile flow effect to the aspiration procedure and requiring a consumable intermediary attachment for aspiration pumping. Also, because the pump acts directly on the intermediary consumable attachment, instead of on the fluid to be displaced, the power requirements and necessary motor size are increased. In addition, peristaltic pumps do not allow for the most efficient displacement of viscous fluid or fluid containing debris and other material.
Alternatively, vacuum pumps placed in surgical consoles located a distance away from the patient, such as Venturi pumps or rotary vane pumps (bladed centrifugal pumps), may be utilized. However, rotary vane pumps have various deficiencies that limit the usefulness of such pumps in ophthalmic applications. Pumps employing vanes, paddles, blades, etc. operate by colliding with and physically redirecting the fluid being displaced. This method of operation introduces vibrations and turbulence to the fluid, which impedes the movement of the fluid and the overall efficiency of the system. In addition, rotary vane pumps can have cavitation problems, low efficiency when pumping viscous fluids, and a low resistance to wear when pumping abrasive fluids.
A need exists for a pump designed for use in ophthalmic surgeries that displaces fluids in such a manner as to allow movement along the path of least resistance, thereby reducing pulsatile flow, turbulence, and cavitation in the fluid, increasing pumping efficiency, and increasing pump resistance to wear.